Could someone please clarify about Sig Figs?

[Bita Ghanei 1F]

When is 0 considered a significant figure and when is it not?
When do you round up or down if the number ends in 5?

Thanks in advance :)

[Paul Hage 2G]

0 is considered a significant figure if it appears between two non-zero numbers (i.e. 104)
0 is also considered significant if it comes after nonzero numbers after a decimal (i.e. 1.300)
However, the zeros that come after a decimal but before the nonzero numbers are NOT significant (i.e. 0.0003)
If a number ends in 5 and you need to round to the digit before it, you would just round the number before the 5 up by 1.
Hope that helps.

[pauline young 1L]

So if it’s 0s after the decimal: any 0 before actual numbers don’t count as sigfig but any 0 after the actual numbers do count.
In addition, if the number is, say, 100 then sigfig is 1 digit. but if it’s 100. (notice the decimal) then the sigfig becomes 3 digits. if it’s 100.0 then it’s 4 and so on.
As for 5s you should always be rounding them up.
idk if that made sense but hope it helps!

[Jordan Young 2J]

There is also a document on Mr. Lavelle's website called "Everything you wanted to know about Sig Fig" if you want more clarification, but I think the above replies explains it pretty well. Zeros are only significant if they are between two numbers (ex: 705) or at the end of a number with decimals (ex: 1.50). They aren't significant if they are before a number with decimals (ex: 0.05).

[KDang_1D]

Everything on zeros is already explained well!

For numbers ending in 5, Dr. Lavelle's PDF on his website says that 5's round to the nearest even number. For example, 7.75 would become 7.8 whereas 7.65 would become 7.6. However, if there are more digits included, for example 7.654, it would round up to 7.7 instead since the 0.004 makes it closer to the greater value.